Apparatus and method for space-division multiplexing optical coherence tomography

Abstract

A space-division multiplexing optical coherence tomography apparatus and system is provided. In one embodiment, the system includes a light source, a reference arm, and a sample arm. The sample arm splits the sampling light into a plurality of sampling beams which may be scanned simultaneously onto a surface of a sample. An optical delay may be introduced into the sampling beams before scanning. A plurality of reflected light signals returned from the sample is collected. In one arrangement, the signals may be combined to produce a single reflected light signal. The reflected light signal(s) and a reference signal are combined to produce an interference signal comprising data representative of digitized images captured of the actual object. In one embodiment, a single sample arm may be used for scanning and collecting image data. A related method is also provided.

What is claimed is: 
     
       1. An optical coherence tomography system with space-division multiplexing, the system comprising:
 a long coherence light source producing light having a coherence length greater than 5 mm to provide optimal imaging depth range; 
 a first optical device configured to split the light into reference light and sampling light; 
 a non-sweeping reference arm receiving the reference light and producing a reference light signal; 
 a second optical device arranged on a sample arm and configured to split the sampling light into a plurality of sampling beams and transmit the plurality of sampling beams simultaneously; 
 an optical delay element configured to produce an optical delay between the plurality of sampling beams; 
 a scanner arranged to receive and configured to simultaneously scan the plurality of sampling beams onto multiple different sampling locations on a surface of a sample; 
 the second optical device operable to simultaneously receive a plurality of reflected light signals returned from the multiple sampling locations; 
 a third optical device configured to generate a plurality of interference signals based on simultaneously receiving the plurality of reflected light signals returned from the multiple sampling locations on the surface of the sample produced by the plurality of sampling beams and the reference light signal; 
 wherein the interference signals includes data representing digitized images of all of the multiple sampling locations simultaneously from the sample. 
 
     
     
       2. The system of  claim 1 , wherein the first optical device is an optical coupler operable to divert the reference light to the reference arm and to divert the sampling light to the sample arm. 
     
     
       3. The system of  claim 1 , further comprising a single sample arm which includes the second optical device, the sample arm transmitting the plurality of sampling beams to the scanner. 
     
     
       4. The system of  claim 1 , wherein the second optical device is an optical fiber splitter. 
     
     
       5. The system of  claim 4 , wherein the optical splitter is planar lightwave circuit splitter. 
     
     
       6. The system of  claim 1 , wherein the second optical device is a microlens array. 
     
     
       7. The system of  claim 6 , wherein the optical delay element comprises a plurality of glass or plastic members each having a different thickness and receiving a portion of the sampling light from the microlens array. 
     
     
       8. The system of  claim 1 , further comprising a balanced detector arranged and operable to detect the interference signal. 
     
     
       9. The system of  claim 1 , wherein the optical delay element comprises an optical fiber array comprised of plurality of optical fibers each having a different length and conveying one of the plurality of sampling beams. 
     
     
       10. The system of  claim 1 , wherein the second optical device is further configured to combine the reflected light signals from the sample into a single detection signal containing the reflected light signals, the detection signal being transmitted to the at least one third optical device. 
     
     
       11. The system of  claim 1 , wherein the third optical device is an optical coupler. 
     
     
       12. The system of  claim 1 , wherein the light source is a wavelength tunable light source. 
     
     
       13. The system of  claim 12 , wherein the light source is a vertical-cavity surface-emitting laser diode. 
     
     
       14. The system of  claim 1 , further comprising a fourth optical device configured to divert a portion of the light to a Mach-Zehnder interferometer, the Mach-Zehnder interferometer configured and operable to clock acquisition of the reflected light signals returned from the surface of the sample. 
     
     
       15. The system of  claim 1 , further comprising a high speed data acquisition card and computer processor configured to capture and process the interference signal and generate a visual display of the actual images of the sample on a display device. 
     
     
       16. An optical coherence tomography system with space-division multiplexing, the system comprising:
 a long coherence light source producing light having a coherence length greater than 5 mm to provide optimal imaging depth range; 
 a first optical coupler configured to divide the light into reference light and sampling light; 
 a non-sweeping reference arm defining a first optical light path, the reference arm receiving the reference light and generating a reference light signal based on the reference light; 
 a single sample arm defining a second optical light path and receiving the sampling light; 
 an optical fiber splitter arranged on the sample arm and dividing the sampling light into a plurality of sampling light beams; 
 an optical delay element comprising a plurality of optical fibers each having a different length and conveying one of the plurality of sampling light beams, the optical fibers producing an optical delay between the plurality of sampling beams; 
 a scanner receiving and simultaneously scanning the plurality of sampling beams onto multiple different sampling locations on a surface of a sample; 
 the optical fiber splitter operable to simultaneously receive a plurality of reflected light signals returned from the multiple sampling locations produced by each of the plurality of sampling beams; 
 a second optical coupler receiving and combining the reference light signal and the plurality of reflected light signals each returned simultaneously from the multiple sampling locations on the surface of the sample produced by each of the plurality of sampling beams to produce a plurality of interference signals each associated with one of the plurality of reflected light signals; 
 wherein the interference signals includes data representing digitized images of all of the multiple sampling locations simultaneously from the sample. 
 
     
     
       17. The system of  claim 16 , wherein the sampling light enters the optical splitter via a single optical fiber and each sampling beam exits the optical splitter via an optical fiber forming an array comprising a plurality of optical fibers. 
     
     
       18. The system of  claim 17 , wherein the optical splitter is planar lightwave circuit splitter. 
     
     
       19. The system of  claim 16 , further comprising a balanced detector operable to detect the interference signal. 
     
     
       20. The system of  claim 16 , wherein the light source is a wavelength tunable laser. 
     
     
       21. The system of  claim 16 , wherein the light source is a broadband light source. 
     
     
       22. A method for imaging a sample using a space-division multiplexing optical coherence tomography system, the method comprising:
 providing an optical coherence tomography system comprising a long coherence light source producing light having a coherence length greater than 5 mm to provide optimal imaging depth range, a non-sweeping reference arm defining a first optical path, and a sample arm defining a second optical path; 
 dividing the light from the light source into reference light and sampling light; 
 transmitting the reference light to the reference arm to produce a reflected light signal; 
 transmitting the sampling light to the sample arm; 
 splitting the sampling light into a plurality of sampling beams on the sample arm; 
 producing an optical delay between the plurality of sampling beams; 
 simultaneously scanning the plurality of sampling beams onto a surface of a sample at multiple different sample locations; 
 collecting a plurality of reflected light signals each returned from the surface of the sample produced by each of the plurality of sampling beams; 
 combining the plurality of reflected light signals into a single reflected light signal comprised of the plurality of reflected light signals; 
 combining the single reflected light signal comprised of the plurality of reflected light signals and the reference light signal to produce a plurality of interference signals, the interference signals comprising data representing digitized images of all of the multiple different sample locations simultaneously from the sample. 
 
     
     
       23. The method of  claim 22 , wherein a single sample arm is provided. 
     
     
       24. The method of  claim 22 , wherein the splitting step is performed using an optical splitter. 
     
     
       25. The method of  claim 22 , further comprising detecting the interference signal using a balanced detector. 
     
     
       26. The method of  claim 22 , further comprising transmitting a portion of the light from the light source to a Mach-Zehnder interferometer to clock acquisition of the interference signal. 
     
     
       27. The method of  claim 22 , wherein the step of producing the optical delay includes transmitting each of the sampling beams in one of a plurality of optical fibers each having a different length.